4π radiation therapy is a new treatment strategy for increasing dose conformity and normal tissue sparing using e.g. highly non-coplanar treatment angles and non-isocentric treatment angles. 4π radiation therapy even includes applying the thereby resulting changes in treatment couch position (translational and rotational) during beam-on, e.g. during an arc treatment. Image-guided radiotherapy (IGRT) systems like ExacTrac® (a product of Brainlab AG) are so far only prepared to monitor the position of a target having a fixed geometric alignment to the treatment machine (alignment of treatment couch to the linear accelerator (Linac) during beam-on. So far any movement of the couch during beam-on has been suppressed.
IGRT systems like ExacTrac® are so far only prepared to monitor the position of a target having a fixed geometric alignment to the treatment machine (alignment of treatment couch to Linac) during beam-on. So far, there has been one planned alignment of patient to treatment system during beam-on in radiotherapy (before 4π radiation therapy was introduced).
The present invention is designed to provide an IGRT system that is capable of monitoring the position of the patient even if the alignment between couch/treatment table and the linear accelerator changes during beam-on.
The present invention can be used in connection with a system for image-guided radiotherapy such as ExacTrac®, a product of Brainlab AG.
Aspects of the present invention, examples and exemplary steps and their embodiments are disclosed in the following. Different exemplary features of the invention can be combined in accordance with the invention wherever technically expedient and feasible.